But since df is called many times by the (old)pup_event_frontend_d and freememapplet[_tray],
it would add a little to the load average .
IMHO the link /etc/mtab -> /proc/mounts
should be created by /etc/rc.d/rc.sysinit after /proc is mounted ,
so it could be omitted in any userspace scripts .
Risky , probably if something removes /etc/mtab , but I cannot think of anything else but the user, and that could remove also any other important files in /etc .